The processing of carbonaceous feedstock or biomass material to produce chemicals or fuels can be accomplished by pyrolysis. Pyrolysis is characterized by the thermal decomposition of materials in an oxygen-poor or oxygen-free atmosphere (i.e., significantly less oxygen than required for complete combustion). In the past, pyrolysis has referred to slow pyrolysis whose equilibrium products included non-reactive solids (char and ash), liquids (tar and/or pyroligneous liquor), and non-condensable gases.
More recently, it has been recognized that pyrolysis can be carried out through a fast (rapid or flash) pyrolysis method where finely divided feedstock is rapidly heated to between 150 and 600° C. and the reaction time is kept short, i.e. on the order of seconds. Such fast pyrolysis results in high yields of primary, non-equilibrium liquids and gases (including valuable chemicals, chemical intermediates, petrochemicals and fuels).
The non-equilibrium liquids (or bio-oil) produced by fast pyrolysis are suitable as a fuel for clean, controlled combustion in boilers and for use in diesel and stationary turbines. Accordingly, it is desirable to develop improved fast pyrolysis processes and equipment to better produce bio-oil from biomass.